The present disclosure relates to a technology for measuring a distance using acoustic signals.
Measurement using a tape measure or other tool, photonic distance measurement using laser beams and so on, and sonic distance measurement using ultrasonic waves are among distance measurement techniques. Although ordinary people normally use a tape measure, not many usually carry their tape measure with them. If one wishes to measure the length of an object or the distance between two points when he or she is away from home, there is no other alternative but to make a rough measurement on the basis of the distance between the thumb and small finger or the distance between the left and right hands with the two hands spread sideways in the absence of a tape measure.
Smartphones are usually carried by many people with them. Smartphones incorporate a speaker and a microphone. Further, recent years have witnessed a large number of wearable terminals such as smart watches coming onto the market. Some wearable terminals designed to support a verbal communication function incorporate a speaker and a microphone.